Charge-Induced Spin Torque in Anomalous Hall Ferromagnets

Abstract

We demonstrate that spin-orbit coupled electrons in a magnetically doped system exert a spin torque on the local magnetization, without a flowing current, when the chemical potential is modulated in a magnetic field. The spin torque is proportional to the anomalous Hall conductivity, and its effective field strength may overcome the Zeeman field. Using this effect, the direction of the local magnetization is switched by gate control in a thin film. This charge-induced spin torque is essentially an equilibrium effect, in contrast to the conventional current-induced spin-orbit torque, and, thus, devices using this operating principle possibly have higher efficiency than the conventional ones. In addition to a comprehensive phenomenological derivation, we present a physical understanding based on a model of a Dirac-Weyl semimetal, possibly realized in a magnetically doped topological insulator. The effect might be realized also in nanoscale transition materials, complex oxide ferromagnets, and dilute magnetic semiconductors.

5 pages, 1 figure

References in corpus (5)

• Discovery of a Weyl Fermion Semimetal and Topological Fermi Arcs
• Quantized Anomalous Hall Effect in Magnetic Topological Insulators
• Spin Transfer Torques
• Anomalous Hall Effect in Weyl Metals
• Spin and Orbital Magnetic Response on the Surface of a Topological Insulator

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• Photovoltaic Chiral Magnetic Effect
• Magnetic textures and dynamics in magnetic Weyl semimetals
• Molecular Beam Epitaxy of thin HfTe2 semimetal films
• Anomalous Hall Effect and Spontaneous Orbital Magnetization in Antiferromagnetic Weyl Metal
• Two-orbital effective model for magnetic Weyl semimetal in Kagome-lattice shandite
• Voltage-driven magnetization switching and spin pumping in Weyl semimetals
• Spin textures and spin-wave excitations in doped Dirac-Weyl semimetals
• Unified theory of magnetization dynamics with relativistic and nonrelativistic spin torques
• Spin-orbital magnetic response of relativistic fermions with band hybridization
• Spin and charge transport in topological nodal-line semimetals
• Equilibrium current vortices in rare-earth-doped simple metals
• Microscopic theory of electrically induced spin torques in magnetic Weyl semimetals
• Time-reversal invariant resonant backscattering on a topological insulator surface driven by a time-periodic gate voltage